sum of all digits in the number by python-CodePudding

Write a python program to calculate sum of digits of a number. and pls explain it line by line as I am new please.

I am screeching it online and found something like this :-

sum = 0
while (n != 0):
   
    sum = sum   (n % 10)
    n = n//10

I don't understand the use of these 2 line please explain it

sum = sum   (n % 10)
        n = n//10

and suggest me if you guys know any another ways to slove it quick and easily? thank you

CodePudding user response：

# Extract the last digit of the number
(n % 10)

Using the modulus operator (%) to get the remainder when n is divided by 10. (e.g., if n is 123, then n % 10 would be 3)

# Add it to the sum
sum = sum   (n % 10)

This is to just add it to the sum variable.

# Remove the last digit from the number
n //= 10

Using the floor division operator (//) to divide n by 10 and assign the result back to n. For example, if n is 123, then n // 10 would be 12.

CodePudding user response：

Prev. post has explained details each of the original code steps. It's to calculate the digit sum. (to make it quicker)

Alternatively, you could do this one-liner:

Explain: convert the number to string then loop and sum the int(x)

Note - since the sum is Python built-in - try to avoid using it as the variable name.

n = 123

digit_sum = sum(int(x) for x in str(n))  
# 6

CodePudding user response：

so basically while loop runs till n becomes 0 let's take an example given n=2438 initially sum is 0

checking is n==0 no... Enter the while loop

`sum = sum   (n % 10)` -> sum=0 8  as 2438=8 which is remainder..!
`n = n//10` -> n=243 after division as you can see the last digit is removed ..!

check is n==0 no.. enter the loop

`sum = sum   (n % 10)` -> sum=8 3  as 243=3 which is remainder..!
`n = n//10` -> n=24 after division as you can see the last digit is removed ..!

as you can see above two steps .

sum=11 4
n=2

sum=15 2
n=0

check is n==0 yes the while loop breaks..!

print the sum as you have obtained the result

As you are beginner you should come up with the simple answer like..

n=2438
n=str(n)      #   2438 converted into "2438"
total_sum_of_digit=0
for i in n:   # loop runs as it converted into string..
    total_sum_of_digit =int(i)   #converted string digit to int digit and add into total_sum_of_digit
print(total_sum_of_digit)

List comprehension is better option.. but you should go with the beginner level to the such above topics..